CN109188121B

CN109188121B - Fault detection method for rotating rectifier in static state of three-stage starting/generator

Info

Publication number: CN109188121B
Application number: CN201810919146.4A
Authority: CN
Inventors: 孙承浩; 刘卫国; 祝宇杰; 孟涛; 庞基; 李丹
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2018-08-14
Filing date: 2018-08-14
Publication date: 2020-09-08
Anticipated expiration: 2038-08-14
Also published as: CN109188121A

Abstract

The invention relates to the field of three-level starting/generator fault detection, and when an exciter stator winding is in a three-phase exciting winding structure, the frequency f is applied to an exciter_esThe three-phase excitation voltage of (2); applying high-frequency voltage signal u to three-phase winding of main generator stator_Ah(t)、u_Bh(t)、u_Ch(t) the high-frequency voltage signal is formed by a high-frequency sine wave voltage u under an αβ coordinate system_αh(t) and u_βh(t) carrying out CLARK inverse transformation to obtain the product under an ABC coordinate system; detecting three-phase exciting current i on exciter stator side_eas、i_ebsAnd i_ecsCLARK conversion is carried out on the collected three-phase exciting current to obtain equivalent two-phase exciting current i_eαsAnd i_eβsAnd carrying out harmonic analysis on the equivalent two-phase excitation current by using a fast Fourier analysis (FFT) method to judge whether the rotary rectifier is in a fault state: short circuit or open circuit.

Description

Fault detection method for rotating rectifier in static state of three-stage starting/generator

Technical Field

The invention belongs to the field of fault detection of three-level starting/generators, and relates to a fault detection method for a rotating rectifier under a static state of a three-level starting/generator, in particular to a fault detection method for injecting rotating high-frequency voltage signals into an equivalent alpha-phase winding and an equivalent beta-phase winding of a stator of a main generator, collecting exciting current at the side of the stator of an exciter and extracting characteristic signals.

Background

The three-stage synchronous generator is widely applied to the existing aviation power supply system due to the unique advantages of the three-stage synchronous generator. With the development of multi/full electric aircrafts, how to realize the starting and power generation integration of the three-stage type motor becomes a research hotspot. Fig. 1 is a structural view of a three-stage motor in which an exciter has a three-phase field winding structure, and is mainly structurally characterized by including a sub-exciter, an exciter, a rotating rectifier, a main generator, and the like, in which a stator and a rotor are integrally assembled, respectively. The exciter provides exciting current for the main generator through rectification of the rotating rectifier, so whether the rotating rectifier fails or not is important to whether the system can operate normally or not. The high centrifugal and thermal stresses also cause the failure rate of the rotating rectifier to be much higher than other components due to the coaxial mounting with the main generator. In conclusion, the research on the fault detection of the rotary rectifier is of great significance. In addition, the aviation three-stage motor is a high-power-density combined motor, and the electromagnetic coupling and mechanical vibration of the system can generate serious interference on the mechanical position sensor, so that the reliability of the system is greatly reduced. It is therefore desirable to develop rotary rectifier fault detection studies without mechanical position sensors. Faults of the rotating rectifier can be divided into open circuit faults and short circuit faults, and excitation output capacity of the rotating rectifier is reduced no matter what faults occur, so that load capacity of a system is reduced, and starting failure is caused. Therefore, the rotating rectifier must be fault-detected before the system is started.

At present, the fault detection methods of the rotating rectifier are many and mainly divided into two categories:

(1) method based on generator topology. The method mainly comprises an auxiliary detection coil method, a main exciter stator current harmonic analysis method and a main generator stator voltage harmonic analysis method. Such methods cannot be applied to three-stage starter/generators due to the large difference in topology between three-stage starter/generators and conventional three-stage generators.

(2) A method based on a starter/generator topology. Such methods mainly include exciter rotor current harmonic analysis. The exciter rotor current acquisition requires estimation using accurate rotor position information and motor parameters, and it is clear that the application of this method to a three-stage starter/generator without position sensors is greatly limited.

Disclosure of Invention

Technical problem to be solved

In order to avoid the defects of the prior art, the invention provides a fault detection method of a rotating rectifier under the static state of a three-level starting/generator, and provides a fault detection method of the rotating rectifier under the static state of the three-level starting/generator based on high-frequency signal injection, namely a main generator stator side injection signal and an exciter stator side detection signal.

Technical scheme

A fault detection method for a rotating rectifier under a static state of a three-level starting/generator is characterized by comprising the following steps:

step 1: when the exciter stator winding is in a three-phase exciting winding structure, applying a frequency f to the exciter_esThe three-phase excitation voltage of (2);

when the exciter stator is in a two-phase winding structure, the exciter is applied with the following components: carrying out CLARK on the three-phase excitation voltage to convert the three-phase excitation voltage into equivalent two-phase winding excitation voltage;

the voltage frequency is unchanged before and after transformation;

step 2: applying high-frequency voltage signal u to three-phase winding of main generator stator_Ah(t)、u_Bh(t)、u_Ch(t) the high-frequency voltage signal is formed by a high-frequency sine wave voltage u under an αβ coordinate system_αh(t) and u_βh(t) is obtained by CLARK inverse transformation to ABC coordinate system, and the high-frequency sine wave voltage u is obtained_αh(t) and u_βhThe expression of (t) is as follows:

wherein U is_h、f_hThe amplitude and the frequency of high-frequency voltage injected into the main generator α shaft and the main generator β shaft under the αβ coordinate system;

and step 3: detecting three-phase exciting current i on exciter stator side_eas、i_ebsAnd i_ecsCLARK conversion is carried out on the collected three-phase exciting current to obtain equivalent two-phase exciting current i_eαsAnd i_eβsCarrying out harmonic analysis on the equivalent two-phase excitation current by using a fast Fourier analysis (FFT) method;

when the exciter stator is of a two-phase winding structure, directly collecting two-phase exciting current and carrying out harmonic analysis on the equivalent two-phase exciting current by using a fast Fourier analysis (FFT) method;

and 4, step 4: if both the two-phase exciting currents contain frequency f_h-f_esAnd f_h+f_esBut does not contain a harmonic component of frequency f_hThe harmonic component of (2), the rotating rectifier has no fault; if both the two-phase exciting currents contain frequency f_h-f_esAnd f_h+f_esWhile at least one phase current has a frequency f_hThe harmonic component of (a), then the rotating rectifier is in a fault state: short circuit or open circuit.

Advantageous effects

The invention provides a fault detection method for a rotating rectifier under a static state of a three-level starting/generator_esThe three-phase excitation voltage of (2); applying high-frequency voltage signal u to three-phase winding of main generator stator_Ah(t)、u_Bh(t)、u_Ch(t) the high-frequency voltage signal is formed by a high-frequency sine wave voltage u under an αβ coordinate system_αh(t) and u_βh(t) carrying out CLARK inverse transformation to obtain the product under an ABC coordinate system; detecting three-phase exciting current i on exciter stator side_eas、i_ebsAnd i_ecsCLARK conversion is carried out on the collected three-phase exciting current to obtain equivalent two-phase exciting current i_eαsAnd i_eβsAnd carrying out harmonic analysis on the equivalent two-phase excitation current by using a fast Fourier analysis (FFT) method to judge whether the rotary rectifier is in a fault state: short circuit or open circuit.

The invention has the following advantages: 1) the difference of the transmission rule of the high-frequency signals in the normal and fault states of the rotating rectifier is fully utilized, and the dependence on the position of a motor rotor and motor parameters is avoided; 2) the data processing procedure and the detection method are relatively simple.

Drawings

FIG. 1: three-stage starter/generator configuration

FIG. 2: exciter three-phase stator current waveform during normal work of rotary rectifier

FIG. 3: exciter three-phase stator current waveform when one tube of rotary rectifier is broken

FIG. 4: exciter three-phase stator current waveform when one tube of rotary rectifier is short-circuited

FIG. 5: exciter stator equivalent two-phase current harmonic analysis during normal work of rotating rectifier

a: carrying out alpha phase current harmonic analysis; b: harmonic analysis of beta phase current

FIG. 6: exciter stator equivalent two-phase current harmonic analysis when one tube of rotating rectifier is broken

FIG. 7: exciter stator equivalent two-phase current harmonic analysis when one tube of rotating rectifier is short-circuited

Detailed Description

The invention will now be further described with reference to the following examples and drawings:

step 1: the exciter of the three-stage motor is of a three-phase exciting winding structure, three-phase alternating-current voltage with 120-degree electrical angle difference is applied to the three-phase exciting winding, the amplitude of the alternating-current voltage is 70V, and the frequency of the alternating-current voltage is 80 Hz;

step 2: applying high-frequency voltage signal u to three-phase winding of main generator stator_Ah(t)、u_Bh(t)、u_Ch(t) the high-frequency signal is formed by a high-frequency square wave voltage u under the αβ coordinate system_αh(t) and u_βh(t) is obtained by carrying out CLARK inverse transformation to an ABC coordinate system. u. of_αh(t) and u_βh(t) is as follows:

i.e. the injection of high frequency voltage amplitude U_h30V, frequency f_h＝1000Hz。

And step 3: detecting three-phase exciting current i on exciter stator side under normal, one tube open and one tube short-circuit states of rotating rectifier respectively_eas、i_ebsAnd i_ecsAs shown in fig. 2, 3 and 4. CLARK conversion is respectively carried out on the three-phase exciting current collected in the three states to obtain equivalent two-phase exciting current i_eαsAnd i_eβsAnd performing harmonic analysis on the equivalent two-phase excitation current by using FFT, as shown in fig. 5, 6, and 7.

And 4, step 4: as can be seen from fig. 5, in the normal state of the rotating rectifier, the equivalent two-phase exciting currents on the stator side of the exciter obviously contain harmonic components with frequencies of 920Hz and 1080Hz, but almost no harmonic component with frequency of 1000Hz (about 1.5mA for the α phase and about 0.9mA for the β phase); as can be seen from fig. 6, in the open-circuit state of one tube of the rotating rectifier, the equivalent two-phase field current on the stator side of the exciter contains harmonic components with frequencies of 920Hz and 1080Hz, while the β -phase current obviously contains a harmonic component with a frequency of 1000Hz (about 10.5 mA). As can be seen from fig. 7, in the short-circuit state of one tube of the rotating rectifier, the equivalent two-phase field current on the stator side of the exciter contains harmonic components with frequencies of 920Hz and 1080Hz, while the β -phase current obviously contains a harmonic component with a frequency of 1000Hz (about 11.1 mA).

Claims

1. A fault detection method for a rotating rectifier under a static state of a three-level starting/generator is characterized by comprising the following steps:

step 2:applying high-frequency voltage signal u to three-phase winding of main generator stator_Ah(t)、u_Bh(t)、u_Ch(t) the high-frequency voltage signal is formed by a high-frequency sine wave voltage u under an αβ coordinate system_αh(t) and u_βh(t) is obtained by CLARK inverse transformation to ABC coordinate system, and the high-frequency sine wave voltage u is obtained_αh(t) and u_βhThe expression of (t) is as follows: